Hi Kieran,
I have a multi-threaded app and I'm starting to run into deadlock issues on EC
locking/unlocking (OSC really). After a weekend of digging and researching I
think your solution is the answer.
Question #1: Is this the final, dust-settled version?
Question #2: Do you always use a new EOObjectStore in your threads? It seems
your implementation depends upon it. If so, what's your philosophy on how many
you create and how long they live? I have tens of thousands of threads running
per instance per day (only a few at a time) and something tells me creating a
new OS for each is a bad idea.
Thanks,
Jon
On 12/3/09 1:31 PM, Kieran Kelleher wrote:
OK, this is the final concurrent utility code to provide manual locking ec's in
a app with safeLocking on. And just for fun and Ricardo's enjoyment of
anonymous classes ;-), the factory is an anonymous static class and its _create
method returns anonymous ERXEC's with the two methods over-riden as per Anjo's
suggestion.
/**
*AnonymousERXECfactorythatcreatesmanuallockingec'sinanappwheresafeLockingisonbydefault
*/
private static ERXEC.Factory manualLockingEditingContextFactory = new
ERXEC.DefaultFactory() {
@Override
protected EOEditingContext _createEditingContext(EOObjectStore parent) {
return new ERXEC(parent == null ? EOEditingContext.defaultParentObjectStore() :
parent) {
@Override
public boolean useAutoLock() {return false;}
@Override
public boolean coalesceAutoLocks() {return false;}
};
}
};
/**
*@returnaregularERXECwithnoauto-lockingfeatures
*/
public static EOEditingContext newManualLockingEditingContext() {
returnmanualLockingEditingContextFactory._newEditingContext();
}
/**
*Idonotwantautolockinginnon-requestthreads
*
*@paramparent
*@returnanERXECwithsafeLockingpropertiesturnedOFF.
*/
public static EOEditingContext newManualLockingEditingContext(EOObjectStore
parent) {
returnmanualLockingEditingContextFactory._newEditingContext(parent);
}
On Dec 3, 2009, at 2:54 PM, Mike Schrag wrote:
i think we're talking two different things ... if you have an empty superclass
constructor and you don't declare any constructors, then yes, there is an
implicit constructor created in your subclass that calls super (as well, if you
DO declare a constructor and there is an empty super constructor, implicitly a
super() is added to the top of your constructor). in this case, because the
anonymous subclass is declared as new ERXEC(os), it's actually calling the
ERXEC(ObjectStore) constructor (which I PRESUME java secretly added into your
subclass with a super(os) call -- this is a little different than a normal
class). However, Kieran's specifically talking about the
ERXEC.newEditingContext() factory method, which you're bypassing here by
explicitly subclassing ERXEC and instantiating the class directly.
ms
On Dec 3, 2009, at 2:45 PM, Ricardo J. Parada wrote:
Don't subclasses have an implicit super() to invoke the super class constructor?
On Dec 3, 2009, at 2:38 PM, Kieran Kelleher wrote:
True, but then I would be bypassing the EC factory, which just seems dirty, but
yes, this very good suggestion is an elegant way to do it for sure.
On Dec 3, 2009, at 2:16 PM, Anjo Krank wrote:
PS. And even the above is not perfect protection against an autolock if a
thread gets cpu execution delay between construction statement and the
ec.setCoalesceAutoLocks(false) statement. After setting safelocking props to
false, I should really check if the ec was autolocked and unlock it before
returning .... or even have an ERXEC constructor that takes a safeLocking
boolean param, but that would be two more undesired constructors ....... so
probably making isLockedInThread public (or accessible using reflection) should
do the trick.
In that case, you'd be better with
return new ERXEC(os) {
public boolean useAutoLock() {return false;}
public boolean coalesceAutoLocks() {return false;}
};
Cheers, Anjo
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